The document discusses scaling a web application called Wanelo that is built on PostgreSQL. It describes 12 steps for incrementally scaling the application as traffic increases. The first steps involve adding more caching, optimizing SQL queries, and upgrading hardware. Further steps include replicating reads to additional PostgreSQL servers, using alternative data stores like Redis where appropriate, moving write-heavy tables out of PostgreSQL, and tuning PostgreSQL and the underlying filesystem. The goal is to scale the application while maintaining PostgreSQL as the primary database.

1. Proprietary and
WHILE THE OLD PRESENTATION IS STILL AVAILABLE AFTER THIS SLIDE,
I THINK YOU SHOULD SEE THE NEW ONE INSTEAD! PLEASE CLICK ON THE LINK:
http://bit.ly/1MXxlBL
WARNING:
There is a more recent and updated version of this talk
available on slideshare, it’s called:
“FROM OBVIOUS TO INGENIOUS:
INCREMENTALLY SCALING WEB APPLICATIONS ON POSTGRESQL”
presented at

2. Proprietary and
Confidential
Konstantin Gredeskoul
CTO, Wanelo.com
12-Step Program for Scaling Web
Applications on PostgreSQL
@kig
@kigster

3. Proprietary and
And why should you care?
What does it mean, to scale on top of
PostgreSQL?

4. Proprietary and
Scaling means supporting more
work load concurrently, where work
is often interchanged with users
But why on PostgreSQL?
Because NoNoSQL is hawt! (again)

5. Proprietary and
Relational databases are great at
supporting constant change in
software
They are not as great in “pure
scaling”, like RIAK or Cassandra
So the choice critically depends on
what you are trying to build

6. Proprietary and
Large majority of web applications
are represented extremely well by
the relational model
So if I need to build a new product
or a service, my default choice
would be PostgreSQL for critical
data, + whatever else as needed

7. Proprietary and
This presentation is a walk-through filled
with practical solutions
It’s based on a story of scaling
wanelo.com to sustain 10s of thousand
concurrent users, 3k req/sec
Not Twitter/Facebook scale, but still…
So let’s explore the application to learn a
bit about wanelo for our scalability journey

8. Proprietary and
Founded in 2010, Wanelo (“wah-nee-loh,” from
Want, Need, Love) is a community and a social
network for all of the world's shopping.
Wanelo is a home to 12M products, millions of
users, 200K+ stores, and products on Wanelo
have been saved into collections
over 2B times

9. • move fast with product development
• scale as needed, stay ahead of the curve
• keep overall costs low
• but spend where it matters
• automate everything
• avoid reinventing the wheel
• learn as we go
• remain in control of our infrastructure
Early on we wanted to:

10. Heroku or Not?
Proprietary and
Assuming we want full control of our
application layer, places like Heroku aren’t a
great fit
But Heroku can be a great place to start. It
all depends on the size and complexity of the
app we are building.
Ours would have been cost prohibitive.

11. Foundations of web apps
Proprietary and
• app server (we use unicorn)
• scalable web server in front (we use nginx)
• database (we use postgresql)
• hosting environment (we use Joyent Cloud)
• deployment tools (capistrano)
• server configuration tools (we use chef)
• programming language + framework (RoR)
• many others, such as monitoring, alerting

12. Let’s review… Basic Web App
Proprietary and
/var/pgsql/data
incoming
http
PostgreSQL
Server
/home/user/app/current/public
nginx Unicorn / Passenger
Ruby VM
N x Unicorns
Ruby VM
• no redundancy, no caching (yet)
• can only process N concurrent requests
• nginx will serve static assets, deal with slow clients
• web sessions probably in the DB or cookie

13. First optimizations:
cheap early on, well worth it
Proprietary and
• Personalization via AJAX, so controller actions
can be cached entirely using caches_action
• Page returned unpersonalized, additional AJAX
request loads personalization

14. A few more basic performance
tweaks that go a long way
Proprietary and
• Install 2+ memcached servers for caching and
use Dalli gem to connect to it for redundancy
• Switch to memcached-based web sessions. Use
sessions sparingly, assume transient nature
• Setup CDN for asset_host and any user
generated content. We use fastly.com
• Redis is also an option, but I prefer memcached
for redundancy

15. Proprietary and
browser PostgreSQL
Server
/home/user/app/current/public
nginx Unicorn / Passenger
Ruby VM
N x Unicorns
Ruby VM
memcachedCDN
cache images, JS
Caching goes a long way…
• geo distribute and cache your UGC and CSS/JS assets
• cache html and serialize objects in memcached
• can increase TTL to alleviate load, if traffic spikes

16. Proprietary and
Adding basic redundancy
• Multiple app servers require haproxy
between nginx and unicorn
• Multiple long-running tasks (such as
posting to Facebook or Twitter) require
background job processing framework
• Multiple load balancers require DNS
round robin and short TTL (dyn.com)

17. Proprietary and
PostgreSQL
Unicorn / Passenger
Ruby VM (times N)
haproxy
incoming http
DNS round robin
or failover / HA solution
nginx
memcached
redis
CDN
cache images, JS
Load Balancers
App Servers
single DB
Object Store
User Generated
Content
Sidekiq / Resque
Background WorkersData stores
Transient to
Permanent
this architecture can horizontally scale up as
far the database at it’s center
every other component can be scaled by
adding more of it, to handle more traffic

18. Proprietary and
As long as we can scale the data
store on the backend, we can scale
the app!
Mostly :)
At some point we may hit a limit on TCP/IP
network throughput, # of connections, but
this is at a whole another scale level

19. The traffic keeps climbing…

20. Performance limits are near
Proprietary and
• First signs of performance problems start creeping up
• Symptoms of read scalability problems
• Pages load slowly or timeout
• Users are getting 503 Service Unavailable
• Database is slammed (very high CPU or read IO)
• Symptoms of write scalability problems
• Database write IO is maxed out, CPU is not
• Update operations are waiting on each other, piling up
• Application “locks up”, timeouts
• Replicas are not catching up
• Some pages load (cached?), some don’t

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Both situations may easily result in
downtime

22. Proprietary and
Even though we
achieved 99.99% uptime
in 2013, in 2014 we had
a couple short
downtimes caused by
overloaded replica that
lasted around 5 minutes.
But users quickly
notice…

23. Proprietary and

24. Proprietary and
Perhaps not :)

25. Proprietary and
Common patterns for scaling high traffic web
applications, based on wanelo.com
12-Step Program
for curing your dependency on slow application latency

26. Proprietary and
• For small / fast HTTP services, 10-12ms or lower
• If your app is high traffic (100K+ RPM) I
recommend 80ms or lower
What’s a good latency?

27. Proprietary and
• RubyVM (30ms) + Garbage collection (6ms) is CPU
burn, easy to scale by adding more app servers
• Web services + Solr (25ms), memcached (15ms),
database (6ms) are all waiting on IO
CPU burn vs Waiting on IO?

28. Proprietary and
Step 1:
Add More Cache!

29. Moar Cache!!!
Proprietary and
•Anything that can be cached, should be
•Cache hit = many database hits avoided
•Hit rate of 17% still saves DB hits
•We can cache many types of things…
•Cache is cheap and fast (memcached)

30. Cache many types of things
Proprietary and
• caches_action in controllers is very effective
• fragment caches of reusable widgets
• we use gem Compositor for JSON API. We cache
serialized object fragments, grab them from
memcached using multi_get and merge them
• Shopify open sourced IdentityCache, which
caches AR models, so you can Product.fetch(id)
https://github.com/wanelo/compositor
https://github.com/Shopify/identity_cache

31. But Caching has it’s issues
Proprietary and
• Expiring cache is not easy
• CacheSweepers in Rails help
• We found ourselves doing 4000 memcached
deletes in a single request!
• Could defer expiring caches to background jobs,
or use TTL if possible
• But we can cache even outside of our app:
we cache JSON API responses using CDN (fastly.com)

32. Proprietary and
Step 2:
Optimize SQL

33. SQL Optimization
• Find slow SQL (>100ms) and either remove it, cache
the hell out of it, or fix/rewrite the query
• Enable slow query log in postgresql.conf:
log_min_duration_statement = 80
log_temp_files = 0
• pg_stat_statements is an invaluable contrib module:

34. Fixing Slow Query
Proprietary and
Run explain plan to understand how DB runs the query
Are there adequate indexes for the query? Is the database using
appropriate index? Has the table been recently analyzed?
Can a complex join be simplified into a subselect?
Can this query use an index-only scan?
Can “order by” column be added to the index?
pg_stat_user_indexes and pg_stat_user_tables for seq scans,
unused indexes, cache info

35. SQL Optimization, ctd
Proprietary and
• Instrumentation software such as NewRelic shows slow queries, with
explain plans, and time consuming transactions

36. SQL Optimization: Example
Proprietary and

37. Proprietary and
One day, I noticed lots of temp files
created in the postgres.log

38. Proprietary and
Let’s run this query…
This join takes a whole second to return :(

39. Proprietary and
• Follows table…

40. Proprietary and
• Stories table…

41. Proprietary and
So our index is partial, only on state = ‘active’
So this query is a full table scan…
But there state isn’t used in the query, a bug?
Let’s add state = ‘active’
It was meant to be there anyway

42. Proprietary and
After adding extra condition IO drops significantly:

43. Proprietary and
Step 3:
Upgrade Hardware and RAM

44. Hardware + RAM
Proprietary and
• Sounds obvious, but better or faster hardware is an
obvious choice when scaling out
• Large RAM will be used as file system cache
• On Joyent’s SmartOS ARC FS cache is very effective
• shared_buffers should be set to 25% of RAM or 12GB,
whichever is smaller
• Using fast SSD disk array can make a huge difference
• Joyent’s native 16-disk RAID managed by ZFS instead
of controller provides excellent performance

45. Hardware in the cloud
Proprietary and
• SSD offerings from Joyent and AWS
• Joyents “max” SSD node $12.9/hr
• AWS “max” SSD node $6.8/hr

46. So who’s better?
Proprietary and
• JOYENT
• 16 SSD drives: RAID10 + 2
• SSD Make: DCS3700
• CPU: E5-2690
2.9GHz
• AWS
• 8 SSD drives
• SSD Make: ?
• CPU: E5-2670
2.6Ghz
Perhaps you get what you pay for after all….

47. Proprietary and
Step 4:
Scale Reads by Replication

48. Scale Reads by Replication
Proprietary and
• postgresql.conf (both master & replica)
• These settings have been tuned for SmartOS and our
application requirements (thanks PGExperts!)

49. How to distribute reads?
Proprietary and
• Some people have success using this setup for reads:
app haproxy pgBouncer replica
pgBouncer replica
• I’d like to try this method eventually, but we choose to
deal with distributing read traffic at the application level
• We tried many ruby-based solutions that claimed to do
this well, but many weren’t production ready

50. Proprietary and
• Makara is a ruby gem from
TaskRabbit that we ported
from MySQL to PostgreSQL
for sending reads to replicas
• Was the simplest library to
understand, and port to PG
• Worked in the multi-threaded
environment of Sidekiq
Background Workers
• automatically retries if replica
goes down
• load balances with weights
• Was running in production

51. Special considerations
Proprietary and
• Application must be tuned to support eventual
consistency. Data may not yet be on replica!
• Must explicitly force fetch from the master DB when
it’s critical (i.e. after a user account’s creation)
• We often use below pattern of first trying the fetch, if
nothing found retry on master db

52. Replicas can specialize
Proprietary and
• Background Workers can use dedicated replica not
shared with the app servers, to optimize hit rate for
file system cache (ARC) on both replicas
PostgreSQL
Master
Unicorn / Passenger
Ruby VM (times N)
App Servers Sidekiq / Resque
Background Workers
PostgreSQL
Replica 1
PostgreSQL
Replica 2
PostgreSQL
Replica 3
ARC cache warm with
queries from web traffic
ARC cache warm with
background job queries

53. Big heavy reads go there
Proprietary and
• Long heavy queries should run by the background jobs
against a dedicated replica, to isolate their effect on
web traffic
PostgreSQL
Master
Sidekiq / Resque
Background Workers
PostgreSQL
Replica 1
• Each type of load will produce a unique set of data
cached by the file system

54. Proprietary and
Step 5:
Use more appropriate tools

55. Leveraging other tools
Proprietary and
Not every type of data is well suited for storing in a relational
DB, even though initially it may be convenient
• Redis is a great data store for transient or semi-
persistent data with list, hash or set semantics
• We use it for ActivityFeed by precomputing each feed at write
time. But we can regenerate it if the data is lost from Redis
• We use twemproxy in front of Redis which provides automatic
horizontal sharding and connection pooling.
• We run clusters of 256 redis shards across many virtual zones;
sharded redis instances use many cores, instead of one
• Solr is great for full text search, and deep paginated
sorted lists, such as trending, or related products

56. Proprietary and
True story: applying WAL logs on
replicas creates significant disk write load
But we still have single master DB taking
all the writes…
Replicas are unable to both serve live traffic and
catch up on replication. They fall behind.
Back to PostgreSQL

57. Proprietary and
When replicas fall behind, application generates
errors, unable to find data it expects

58. Proprietary and
Step 6:
Move write-heavy tables out:
Replace with non-DB solutions

59. Move event log out
Proprietary and
• We were appending all user events into this table
• We were generating millions of rows per day!
• We solved it by replacing user event recording system to
use rsyslog, appending to ASCII files
• We discovered from pg_stat_user_tables top table by
write volume was user_events
It’s cheap, reliable and scalable
We now use Joyent’s Manta to analyze this data in
parallel. Manta is an object store + native compute on

60. Proprietary and
For more information about how we migrated
user events to a file-based append-only log, and
analyze it with Manta, please read
http://wanelo.ly/event-collection

61. Proprietary and
Step 7:
Tune PostgreSQL and your
Filesystem

62. Tuning ZFS
Proprietary and
• Problem: zones (virtual hosts) with “write
problems” appeared to be writing 16 times
more data to disk, compared to what virtual file
system reports
• vfsstat says 8Mb/sec write volume
• So what’s going on?
• iostat says 128Mb/sec is actually written to disk

63. Proprietary and
• Turns out default ZFS block size is 128Kb,
and PostgreSQL page size is 8Kb.
• Every small write that touched a page, had to
write 128Kb of a ZFS block to the disk
Tuning Filesystem
• This may be good for huge sequential writes,
but not for random access, lots of tiny writes

64. Proprietary and
• Solution: Joyent changed ZFS block size for our zone,
iostat write volume dropped to 8Mb/sec
• We also added commit_delay
Tuning ZFS & PgSQL

65. Proprietary and
• Many such settings are pre-defined in our open-source
Chef cookbook for installing PostgreSQL from sources
Installing and Configuring PG
• https://github.com/wanelo-chef/postgres
• It installs PG in eg /opt/local/postgresql-9.3.2
• It configures it’s data in /var/pgsql/data93
• It allows seamless and safe upgrades of minor or major
versions of PostgreSQL, never overwriting binaries

66. Additional resources online
Proprietary and
• Josh Berkus’s “5 steps to PostgreSQL
Performance” on SlideShare is fantastic
• PostgreSQL wiki pages on performance tuning
are excellent
• Run pgBench to determine and compare
performance of systems
http://www.slideshare.net/PGExperts/five-steps-perform2013
http://wiki.postgresql.org/wiki/Performance_Optimization
http://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server

67. Proprietary and
Step 8:
Buffer and serialize frequent
updates

68. Counters, counters…
Proprietary and
• Problem: products.saves_count is
incremented every time someone saves a
product (by 1)
• At 100s of inserts/sec, that’s a lot of updates
How can we reduce number of writes and
lock contention?
• Worse: 100s of concurrent requests trying to
obtain a row level lock on the same popular
product

69. Buffering and serializing
Proprietary and
• Sidekiq background job framework has two
inter-related features:
• scheduling in the future (say 10 minutes ahead)
• UniqueJob extension
• Once every 10 minutes popular products are updated by
adding a value stored in Redis to the database value, and
resetting Redis value to 0
• We increment a counter in redis, and enqueue a job
that says “update product in 10 minutes”

70. Buffering explained
Proprietary and
Save Product
Save Product
Save Product
1. enqueue update
request for product
with a delay
PostgreSQL
Update Request already
on the queue
3. Process Job
Redis Cache
2. increment
counter
4. Read & Reset to 0
5. Update Product

71. Buffering conclusions
Proprietary and
• If not, to achieve read consistency, we can
display the count as database value + redis
value at read time
• If we show objects from the database, they
might be sometimes behind on the counter. It
might be ok…

72. Proprietary and
Step 9:
Optimize DB schema

73. MVCC does copy on write
Proprietary and
• Problem: PostgreSQL rewrites the row for most updates (some
exceptions exist, ie non-indexed column, a counter, timestamp)
• But we often index these so we can sort by them
• Rails and Hibernate’s partial updates are not helping
• Are we updating User on each request?
• So updates can become expensive on wide tables

74. Schema tricks
Proprietary and
• Solution: split wide tables into several 1-1
tables to reduce update impact
• Much less vacuuming required when smaller
tables are frequently updated

75. Proprietary and
Don’t update anything on each request :)
id
email
encrypted_password
reset_password_token
reset_password_sent_at
remember_created_at
sign_in_count
current_sign_in_at
last_sign_in_at
current_sign_in_ip
last_sign_in_ip
confirmation_token
confirmed_at
confirmation_sent_at
unconfirmed_email
failed_attempts
unlock_token
locked_at
authentication_token
created_at
updated_at
username
avatar
state
followers_count
saves_count
collections_count
stores_count
following_count
stories_count
Users
id
email
created_at
username
avatar
state
Users
user_id
encrypted_password
reset_password_token
reset_password_sent_at
remember_created_at
sign_in_count
current_sign_in_at
last_sign_in_at
current_sign_in_ip
last_sign_in_ip
confirmation_token
confirmed_at
confirmation_sent_at
unconfirmed_email
failed_attempts
unlock_token
locked_at
authentication_token
updated_at
UserLogins
user_id
followers_count
saves_count
collections_count
stores_count
following_count
stories_count
UserCounts
refactor

76. Proprietary and
Step 10:
Shard Busy Tables Vertically

77. Vertical sharding
Proprietary and
• Heavy tables with too many writes, can be
moved into their own separate database
• For us it was saves: now @ 2B+ rows
• At hundreds of inserts per second, and 4 indexes,
we were feeling the pain
• It turns out moving a single table (in Rails) out is
a not a huge effort: it took our team 3 days

78. Vertical sharding - how to
Proprietary and
• Update code to point to the new database
• Implement any dynamic Rails association
methods as real methods with 2 fetches
• ie. save.products becomes a method on Save
model, lookup up Products by IDs
• Update development and test setup with two
primary databases and fix all the tests

79. Proprietary and
Web App
PostgreSQL
Master (Main Schema)
PostgreSQL
Replica (Main Schema)
Vertically Sharded Database
PostgreSQL
Master (Split Table)
Here the application
connects to main master
DB + replicas, and a single
dedicated DB for the busy
table we moved

80. Vertical sharding, deploying
Proprietary and
Drop in write IO on the main DB after splitting off
the high IO table into a dedicated compute node

81. Proprietary and
For a complete and more detailed account of
our vertical sharding effort, please read our
blog post:
http://wanelo.ly/vertical-sharding

82. Proprietary and
Step 11:
Wrap busy tables with services

83. Splitting off services
Proprietary and
• Vertical Sharding is a great precursor to a
micro-services architecture
• New service: Sinatra, client and server libs,
updated tests & development, CI, deployment
without changing db schema
• 2-3 weeks a pair of engineers level of effort
• We already have Saves in another database,
let’s migrate it to a light-weight HTTP service

84. Adapter pattern to the rescue
Proprietary and
Main App
Unicorn w/ Rails
PostgreSQL
HTTP
Client Adapter
Service App
Unicorn w/Sinatra
Native
Client Adaptor
• We used Adapter pattern to write two client
adapters: native and HTTP, so we can use the lib,
but not yet switch to HTTP

85. Services conclusions
Proprietary and
• Now we can independently scale service
backend, in particular reads by using replicas
• This prepares us for the next inevitable step:
horizontal sharding
• At a cost of added request latency, lots of extra
code, extra runtime infrastructure, and 2
weeks of work
• Do this only if you absolutely have to

86. Proprietary and
Step 12:
Shard Services Backend
Horizontally

87. Horizontal sharding in ruby
Proprietary and
• We wanted to stick with PostgreSQL for critical
data such as saves
• Really liked Instagram’s approach with schemas
• Built our own schema-based sharding in ruby,
on top of Sequel gem, and open sourced it
• It supports mapping of physical to logical shards,
and connection pooling
https://github.com/wanelo/sequel-schema-sharding

88. Schema design for sharding
Proprietary and
https://github.com/wanelo/sequel-schema-sharding
user_id
product_id
collection_id
created_at
index__on_user_id_and_collection_id
UserSaves Sharded by user_id
product_id
user_id
updated_at
index__on_product_id_and_user_id
index__on_product_id_and_updated_at
ProductSaves Sharded by product_id
We needed two lookups, by user_id
and by product_id hence we needed
two tables, independently sharded
Since saves is a join table between
user, product, collection, we did not
need unique ID generated
Composite base62 encoded ID:
fpua-1BrV-1kKEt

89. Spreading your shards
Proprietary and
• We split saves into 8192 logical shards,
distributed across 8 PostgreSQL databases
• Running on 8 virtual zones
spanning 2 physical SSD
servers, 4 per compute node
• Each database has 1024
schemas (twice, because we
sharded saves into two tables)
https://github.com/wanelo/sequel-schema-sharding
2 x 32-core 256GB RAM
16-drive SSD RAID10+2
PostgreSQL 9.3
1
3 4
2

90. Proprietary and
Sample
configuration of
shard mapping to
physical nodes
with read
replicas,
supported by the
library

91. Proprietary and
How can we migrate the data from old non-
sharded backend to the new sharded backend
without a long downtime?

92. New records go to both
Proprietary and
HTTP Service
Old Non-Sharded Backend
New Sharded Backend
1
3 4
2
Read/Write
Background
Worker
Enqueue
Sidekiq Queue
Create Save

93. Proprietary and
HTTP Service
Old Non-Sharded Backend
New Sharded Backend
1
3 4
2
Read/Write
Background
Worker
Enqueue
Sidekiq Queue
Create Save
Migration Script
Migrate old rows
We migrated several times before we got this right…

94. Proprietary and
Swap old and new backends
HTTP Service
Old Non-Sharded Backend
New Sharded Backend
1
3 4
2Read/Write
Background
Worker
Enqueue
Sidekiq Queue
Create Save

95. Horizontal sharding conclusions
Proprietary and
• This is the final destination of any scalable
architecture: just add more boxes
• Pretty sure we can now scale to 1,000, or 10,000
inserts/second by scaling out
• Took 2 months of 2 engineers, including migration,
but zero downtime. It’s an advanced level effort and
our engineers really nailed this.
https://github.com/wanelo/sequel-schema-sharding

96. Putting it all together
Proprietary and
• This infrastructure complexity is not free
• It requires new automation, monitoring,
graphing, maintenance and upgrades, and brings
with it a new source of bugs
• In addition, micro-services can be “owned”
by small teams in the future, achieving
organizational autonomy
• But the advantages are clear when scaling is
one of the requirements

97. Proprietary and
Systems Diagram
incoming http
requests
8-core 8GB zones
haproxy
nginx
Fastly CDN
cache images, JS
Load Balancers
Amazon S3
Product Images
User Profile Pictures
32-core 256GB 16-drive SSD RAID10+2
Supermicro "Richmond"
SSD Make: Intel DCS3700,
CPU: Intel E5-2690, 2.9GHz
PostgreSQL 9.2
Master
Primary Database Schema
4-core 16GB zones
memcached
User and Product Saves, Horizontally Sharded, Replicated
32-core 256GB RAM
16-drive SSD RAID10+2
PostgreSQL 9.3
1
3 4
2
Read Replicas (non SSD)
2
4 2
1
Read Replica (SSD)
PostgreSQL
Async Replicas
32-core 32GB high-CPU instances
Unicorn
Main Web/API App,
Ruby 2.0
Unicorn
Saves Service
haproxy
pgbouncer
iPhone, Android, Desktop clients Makara distributes DB
load across 3 replicas
and 1 master
MemCached Cluster
Redis Clusters for various custom
user feeds, such as product feed
1-core 1GB zones
twemproxy
Redis Proxy Cluster
16GB high-mem 4-core zones
32 redis instances per server
redis-001
redis-256
8GB High CPU zones
Solr Replica
8GB High CPU zone
Solr Master
App Servers + Admin Servers
Cluster of MemCached Servers
is accessed via Dali fault tolerant library
one or more can go down
Apache Solr Clusters
32-core 32GB high-CPU instances
Sidekiq Background
Worker
Unicorn
Saves Service
haproxy
pgbouncer
to DBs
Solr Reads
Solr Updates
Background Worker Nodes
redis
Redis Sidekiq
Jobs Queue / Bus

98. Systems Status: Dashboard Monitoring & Graphing with Circonus, NewRelic, statsd, nagios

99. Backend Stack & Key Vendors
Proprietary and
■ MRI Ruby, jRuby, Sinatra, Ruby on Rails
■ PostgreSQL, Solr, redis, twemproxy
memcached, nginx, haproxy, pgbouncer
■ Joyent Cloud, SmartOS, Manta Object Store
ZFS, ARC Cache, superb IO, SMF, Zones, dTrace, humans
■ DNSMadeEasy, MessageBus, Chef, SiftScience
■ LeanPlum, MixPanel, Graphite analytics, A/B Testing
■ AWS S3 + Fastly CDN for user / product images
■ Circonus, NewRelic, statsd, Boundary,
PagerDuty, nagios:trending / monitoring / alerting

100. Proprietary and
We are hiring!
DevOps, Ruby, Scalability, iOS & Android
Talk to me after the presentation if you are interested in working
on real scalability problems, and on a product used and loved by millions :)
http://wanelo.com/about/play
Or email play@wanelo.com

101. Thanks!
github.com/wanelo
github.com/wanelo-chef
wanelo technical blog (srsly awsm)
building.wanelo.com
Proprietary and
@kig
@kig
@kigster